SALEM COMMUNITY HOSPITAL...Lack of deep sleep tied with blood pressure

September 4, 2011

Not getting enough deep may raise a person's blood pressure, according to a new study published recently in Hypertension: Journal of the American Heart Association. The research indicated that men who got the least deep sleep were 83% more likely to develop than those who got the most sleep.

"Missing out on deep sleep can leave a person feeling groggy and irritable in the morning, but the consequences don't necessarily end there," explained Internal Medicine physician Denis Lunne, M.D. "Over time, too little deep sleep may also take a toll on a person's heart by contributing to high blood pressure."

"Healthy young and middle-aged adults spend about 20% to 25% of their sleeping hours in the stages known as slow-wave sleep. This phase of sleep is named slow-wave because of the brain waves associated with this sleep stage. People with less time spent in slow-wave sleep are more likely to have poor quality sleep. In addition, slow-wave sleep is considered to be important for both memory and mental performance."

Sleep-Blood Pressure Connection

The study was conducted by researchers at the University of California-San Diego and Harvard University, and included 784 men over the age of 65. Researchers determined how much deep sleep the men got by measuring the speed of their brain waves as they slept at night. The participants' sleep quality was assessed by using polysomnography, which is a technique that uses electrodes to track a person's brain activity.

All of the men had normal blood pressure when they underwent the test, which was performed during a single night in their own beds, as opposed to in a sleep lab. The men's blood pressure was measured and their sleep monitored at the start of the study and again about three and a half years later. When the researchers followed up with the men, roughly 31% of the study participants had developed hypertension.

"The study looked at the relationship between sleep characteristics like sleep duration and brain wave activity and the risk of developing high blood pressure among men ages 65 and over," Dr. Lunne said. "Compared to men who spent at least 17% of their sleep time in the slow-wave phase, those who spent less than 4% in this restful state had an 83% higher risk of developing high blood pressure. Men with less slow-wave sleep were also more likely to have poor-quality sleep. This means that they had shorter sleep duration, more awakenings at night, and more severe sleep apnea."

The study's findings add to the growing evidence that slow-wave sleep is important for a person's metabolism and his or her heart health. Although the research doesn't prove a direct link between sleep patterns and hypertension, it suggests that an important aspect of successful aging is maintaining good sleep quality.

"During a normal sleep cycle, the body alternates between deep and light sleep that should leave you feeling awake and alert," Dr. Lunne stated. "If you're still sleepy after a full night in bed, chances are something is happening to prevent your body and brain from entering those deep, restorative levels of sleep."

In addition, changes in the sleep cycle do occur with aging. Deep or slow wave sleep (Stage N3) declines as we age, while light sleep (Stage N1) increases with age. Older adults may spend less time in the more restorative stages of sleep and more time in lighter sleep, and they are also more easily aroused from sleep.

"To maximize slow-wave sleep, it is important to first make sure that you don't have a sleep disorder like sleep apnea or periodic leg movement that may be causing sleep disruptions. However, going to bed and waking up at the same time each day, avoiding alcohol and tobacco before bedtime, and other good sleep hygiene practices can help people sleep longer, and probably more deeply."

Link to Other Sleep Problems?

Previous studies have already linked sleep disorders such as obstructive sleep apnea and sleep-disordered breathing to an increased risk of high blood pressure. Researchers say sleep-disordered breathing is common among older adults and affects up to 60% of the elderly.

"Sleep apnea is a chronic disorder in which a person wakes up struggling for breath several times during the night, and this condition has been strongly linked to hypertension," Dr. Lunne concluded. "Obesity has also been shown to increase the risk of both high blood pressure and sleep apnea, and obesity could play a role in the link between slow-wave sleep and hypertension."

Denis Lunne, M.D., is a Board certified Internal Medicine physician affiliated with Salem Community Hospital's medical staff. His office is located at 107 Birkdale Drive, Suite A in Columbiana.